For what it's worth, we have servers running the Quake 1 campaigns, they can be found in the in-game server list as named:
Quake 1 Nostalgia Trip! (SMB)
Quake: Scourge of Armagon, Nostalgic Edition! (SMB)
Quake: Dissolution of Eternity, Nostalgic Edition! (SMB)

Xonotic runs on the DarkPlaces engine, so the Quake maps are pretty much directly compatible (although, support for Quake 2 maps is relatively new).